This disclosure relates to combined stairway and lift installations.
The term “stair” is commonly used to refer to a single step in a stairway within a building, the whole flight of a stairway within a building being referred to as “the stairs” or as a “staircase”, while the term “steps” may refer to individual “stairs” or to the stairway as a whole in the case of an external stairway to a building or to a stairway within a garden or urban landscape. For convenience and consistency, hereafter, the term “step” is used to refer to an individual step or stair, and “stairway” to refer to a whole flight of such steps, whether internal or external.
It is often required for public buildings, which may have one or more steps at their main entrance, to provide access to wheelchair users. It may also be desirable to provide easier access for prams and pushchairs than attempting to man-handle them up an existing stairway. Access problems may arise not only on entering a building but also between levels within a building.
The simplest way to provide this access is to provide a ramp alongside any stairway. While this will obviously work it is not always a practical solution. Having both a ramp and a stairway takes up a large amount of space, which may not be available. Additionally if the access is being provided to a building of historical or architectural merit it may be undesirable (or, in some jurisdictions, illegal or unlawful) to build a ramp as this will change the external appearance of the building. As an alternative to a stairway inside a building, conventional lifts (elevators) have been provided. In the case of a building of historical or architectural merit, it may not readily be feasible at a later date to incorporate a conventional lift within the existing interior structure of the building without significant alteration to the interior fabric of the building.
EP0912809 Lyons provides a solution to this problem in which steps forming a stairway are horizontally retractable and positioned over a lift platform. Accordingly, as the steps are retracted horizontally, a lift platform is revealed. Following operation of the lift platform to move a wheelchair user from one level to another and return of the platform to its original position, the steps return to their original position, so that the stairway may be used by able-bodied users in conventional fashion. Practical embodiments of this stairway/lift platform system, supplied by Sesame Access Ltd of West Byfleet, Surrey KT14 7LF, have proved very successful. However, this existing system requires space behind the stairway into which individual steps of the stairway may retract. There may not always be sufficient space behind an existing stairway to accommodate such retraction. This space may already contain load bearing members and/or utilities.
At the date of filing the present application, Applicant is aware of two more recent developments as follows, neither of which is entirely successful, for the reasons explained:                A combined stairway and platform lift is supplied by Terry Group Ltd of Knutsford, Cheshire WA16 8PR under the trade designation TSL1000 Domestic Steplift, for which, at the date of filing this application, pictures and a video were available at www.terrylifts.co.uk/ts11000-steplift.html illustrating how this stairway/lift works. A lift platform is provided in front of the stairway. A wheelchair user wheels their wheelchair up a short ramp onto the platform. As the platform rises vertically, individual steps also rise guided by vertically extending railings provided on either side of the stairway until both the platform and the treads of the individual steps all lie in the plane of an upper surface level onto which the wheelchair user may then travel. While this structure need not intrude into space behind the stairway, it requires additional space in front of the stairway and provision of intrusive vertical railings on either side of the stairway. This structure is unlikely to find favour for incorporation into buildings of historical or architectural merit.        An alternative combined stairway and platform lift is made by a company called Swallow Evacuation & Mobility Products Ltd of Birmingham B14 7QQ under the Trademark Flexstep and can be seen in a video at www.youtube.com/watch?vQNoA6LFNPh0. In this model the steps sweep forward as they are lowered to create a flat platform which may be used as a lift. Due to the sweeping motion an overhang is left at the forward edge, which can be inconvenient for wheelchair users. Additionally due to the sweeping motion it would not be possible for the steps to have risers. Particularly when placed outside, risers are desirable in a stairway, since, in addition to giving the stairway a desirable aesthetic appearance they also serve largely to prevent items, such as leaves getting trapped under the stairway and potentially clogging the mechanism.        